How often should you deep clean/clean your PC?

Like cleaning and removing dust from fans, the GPU, the case, cable management, etc. A video I watched talked about how you should deep clean your PC once, or even if needed, twice every two months. Is that a good time frame? What about the time frame of regular cleaning/dusting?

When should you reapply the new thermal paste on your CPU?

This is intended for gaming PCs.
How often should you deep clean/clean your PC?
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